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Abstract

Efficient refueling is one of the basic requirements to sustain themonuclear plasmas in future tokamak based fusion grade reactors. Although injection of crygenic deutrium pellets from the magnetic high field size (HFS) was predicted to have more potential /1/ and at ASDEX Upgrade found to be more efficient /2/ than injection from the low field size(LFS), the technical implementation of HSF refueling remains critically restricted to low velocities (v=240 m/s) due to limited accesibility of the high field size of the torus. The maximum speed available by the ASDEX Upgrade centrifuge /3/ is v= 1200 m/s The required optimism of the system guiding the pellets to the HSF is suggested by analysing the componants (funnel and curved guiding tube), studying their characteristics and the physical process involved. Firstly, impact tests on flat targets to emulate impact in a funnel were performed. Pellets were not reflected but found to quasi-slide along the inner surface of the target after the first impact. The impact velocity perpendicular to the target was found to control the survival of the pellets. At a velocity of about 42 m/s all pellets survived one or more inpacts under angles 3 degrees- 6 degrees. An impact angle of 2 degrees was extrapolated to ensure pellet survival at v= 1200 m/s. Accordingly, a new funnel was designed.

Additional information

Authors: LORENZ A, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);BECK W, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);CIERPKA P, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);HU L, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);LANG P T, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);LANG R S, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE);WEBER G, Max-Planck-Institut fur Plasmaphysik, Garching bei Munchen (DE)
Bibliographic Reference: Article:Optimized pellet Guiding to the Magnetic High Field Side of ASDEX Upgrade, (1998), 1-22
Record Number: 199910410 / Last updated on: 1999-03-19
Category: PUBLICATION
Original language: en
Available languages: en